Respostas

2013-12-11T20:31:37-02:00
Talvez seja f(x) = -2x+5, daí teremos:
f(x) = 0 --> -2x+5 = 0 --> -2x = -5 .(-1) --> 2x = 5 --> x = 5/2
f(x) = 7 --> -2x+5 = 7 --> -2x = 7-5 --> -2x = 2.(-1) --> 2x = -2 --> x = -2/2--> x = -1